333 research outputs found

    Alternative Representations for Codifying Solutions in Permutation-Based Problems

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    Since their introduction, Estimation of Distribution Algorithms (EDAs) have proved to be very competitive algorithms to solve many optimization problems. However, despite recent developments, in the case of permutation-based combinatorial optimization problems, there are still many aspects that deserve further research. One of them is the influence of the codification employed to represent the solutions on the overall performance of the algorithm. When considering classical EDAs, optimizing permutation problems is challenging, and specific mechanisms are needed to hold the restrictions associated with the permutation nature of solutions.In this paper, in addition to the permutation-vector codification, we investigate alternative representations to describe solutions of permutation problems in the context of EDAs. In order to evaluate their influence, we adopted a classical EDA and conducted an experimental study on two different permutation problems and representations for codifying solutions. The results revealed a narrow relationship between the type of combinatorial problem optimized and the selected representation used to codify its solutions. Moreover, the results point out that choosing the appropriate representation to codify solutions of the given permutation problem is critical for the performance of the algorithm

    The idiosyncratic volatility anomaly: Corporate investment or investor mispricing?

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    Most of the literature on the idiosyncratic volatility anomaly has focused on plausible explanations for it based on investor preferences, investor irrationality or market characteristics. Surprisingly, the role of asset-pricing models and firm characteristics in the estimation of idiosyncratic risk measures has been largely neglected. Our results suggest that investment and profitability, presumably driven by managers and therefore linked to idiosyncratic risk, are able to account for the anomaly in a cross-section of stock returns. Moreover, we show that this effect is independent and complementary to the effects related to investor preference for skewness

    Aquaporin-11 Contributes to TGF-β1-Induced Endoplasmic Reticulum Stress in Human Visceral Adipocytes: Role in Obesity-Associated Inflammation

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    Aquaporin-11 (AQP11) is expressed in human adipocytes, but its functional role remains unknown. Since AQP11 is an endoplasmic reticulum (ER)-resident protein that transports water, glycerol, and hydrogen peroxide (H2O2), we hypothesized that this superaquaporin is involved in ER stress induced by lipotoxicity and inflammation in human obesity. AQP11 expression was assessed in 67 paired visceral and subcutaneous adipose tissue samples obtained from patients with morbid obesity and normal-weight individuals. We found that obesity and obesity-associated type 2 diabetes increased (p < 0.05) AQP11 mRNA and protein in visceral adipose tissue, but not subcutaneous fat. Accordingly, AQP11 mRNA was upregulated (p < 0.05) during adipocyte differentiation and lipolysis, two biological processes altered in the obese state. Subcellular fractionation and confocal microscopy studies confirmed its presence in the ER plasma membrane of visceral adipocytes. Proinflammatory factors TNF-α, and particularly TGF-β1, downregulated (p < 0.05) AQP11 mRNA and protein expression and reinforced its subcellular distribution surrounding lipid droplets. Importantly, the AQP11 gene knockdown increased (p < 0.05) basal and TGF-β1-induced expression of the ER markers ATF4 and CHOP. Together, the downregulation of AQP11 aggravates TGF-β1-induced ER stress in visceral adipocytes. Owing to its "peroxiporin" properties, AQP11 overexpression in visceral fat might constitute a compensatory mechanism to alleviate ER stress in obesity

    Reduction of low- and high-grade cervical abnormalities associated with high uptake of the HPV bivalent vaccine in Scotland

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    In Scotland, a national HPV immunisation programme began in 2008 for 12-13 year olds, with a catch-up campaign from 2008-2011 for those under the age of 18. To monitor the impact of HPV immunisation on cervical disease at the population level, a programme of national surveillance was established.  We analysed colposcopy data from a cohort of women born between 1988-1992 who entered the Scottish Cervical Screening Programme (SCSP) and were aged 20-21 in 2008-2012.  By linking datasets from the SCSP and colposcopy services, we observed a significant reduction in diagnoses of cervical intraepithelial neoplasia 1 (CIN 1) (RR 0.71, 95% CI 0.58 to 0.87, p=0.0008), CIN 2 (RR 0.5, 95% CI 0.4, 0.63, p<0.0001) and CIN 3 (RR 0.45, 95% CI 0.35 to 0.58, p< 0.0001) for women who received 3 doses of vaccine compared with unvaccinated women.  To our knowledge, this is one of the first studies to show a reduction of low and high grade cervical intraepithelial neoplasia associated with high uptake of the HPV bivalent vaccine at the population level. These data are very encouraging for countries that have achieved high HPV vaccine uptake

    The use of the individual development plan at minority serving institutions

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    The Individual Development Plan (IDP) is a common mentoring tool in higher education. Students and postdoctoral researchers can use an IDP to facilitate conversations with their mentors and create action plans to support future goals. The entire process helps mentees achieve both short- and long-term objectives. Little is known about how historically underrepresented minority groups are supported during this process. This study investigated IDP implementation at 504 minority serving institutions (MSIs) that primarily serve African American, Hispanic/Latinx, and Native-American populations. Using content analysis, we systematically reviewed the publicly available IDP tools and policies at each MSI. Although several crucial mentoring components and implementation strategies were identified, there was a noticeable absence of emphasis on multicultural mentoring guidance and psychosocial support throughout the process. Our findings offer decision-makers and faculty mentors insights into supporting minority trainees and lay the foundation for future research in the field of IDPs

    Direct detection of dark matter axions with directional sensitivity

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    We study the directional effect of the expected axion dark matter signal in a resonant cavity of an axion haloscope detector, for cavity geometries not satisfying the condition that the axion de Broglie wavelength λa\lambda_a is sufficiently larger than the cavity dimensions LL for a fully coherent conversion, i.e. λa≳2πL\lambda_a \gtrsim 2\pi L. We focus on long thin cavities immersed in dipole magnets and find, for appropriately chosen cavity lengths, an O(1) modulation of the signal with the cavity orientation with respect the momentum distribution of the relic axion background predicted by the isothermal sphere model for the galactic dark matter halo. This effect can be exploited to design directional axion dark matter detectors, providing an unmistakable signature of the extraterrestrial origin of a possible positive detection. Moreover, the precise shape of the modulation may give information of the galactic halo distribution and, for specific halo models, give extra sensitivity for higher axion masses.Comment: 14 pages, 12 figures, prepared for submission to JCA

    Resistin Regulates Pituitary Lipid Metabolism and Inflammation In Vivo

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    The adipokine resistin is an insulin-antagonizing factor that also plays a regulatory role in inflammation, immunity, food intake, and gonadal function and also regulates growth hormone (GH) secretion in rat adenopituitary cells cultures with the adipokine. Although adipose tissue is the primary source of resistin, it is also expressed in other tissues, including the pituitary. The aim of this study is to investigate the possible action of resistin on the lipid metabolism in the pituitary gland in vivo (rats in two different nutritional status, fed and fast, treated with resistin on acute and a chronic way) and in vitro (adenopituitary cell cultures treated with the adipokine). Here, by a combination of in vivo and in vitro experimental models, we demonstrated that central acute and chronic administration of resistin enhance mRNA levels of the lipid metabolic enzymes which participated on lipolysis and moreover inhibiting mRNA levels of the lipid metabolic enzymes involved in lipogenesis. Taken together, our results demonstrate for the first time that resistin has a regulatory role on lipid metabolism in the pituitary gland providing a novel insight in relation to the mechanism by which this adipokine can participate in the integrated control of lipid metabolism

    Comparison of flipped learning and traditional lecture method for teaching digestive system diseases in undergraduate medicine: A prospective non-randomized controlled trial

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    Introduction: This study examined the effects of a large-scale flipped learning (FL) approach in an undergraduate course of Digestive System Diseases. Methods: This prospective non-randomized trial recruited 404 students over three academic years. In 2016, the course was taught entirely in a Traditional Lecture (TL) style, in 2017 half of the course (Medical topics) was replaced by FL while the remaining half (Surgical topics) was taught by TL and in 2018, the whole course was taught entirely by FL. Academic performance, class attendance and student’s satisfaction surveys were compared between cohorts. Results: Test scores were higher in the FL module (Medical) than in the TL module (Surgical) in the 2017 cohort but were not different when both components were taught entirely by TL (2016) or by FL (2018). Also, FL increased the probability of reaching superior grades (scores >7.0) and improved class attendance and students’ satisfaction. Conclusion: The holistic FL model is more effective for teaching undergraduate clinical gastroenterology compared to traditional teaching methods and has a positive impact on classroom attendances
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